Walk-Behind Lawn Mowers by SENIX. Details:Beautify your lawn with the SENIX 20-inch 125 cc lawn mower. This walk-behind lawn mower features a 20-inch steel deck and is powered by a reliable Briggs & Stratton 125 cc gas powered engine that is designed to provide longer engine life, low vibration, and easy maintenance. The 4-stroke engine is eco-friendly offering low emissions, low fuel consumption, no mixing of oil and gas, and low noise. This compact lawn mower is ideal for small to medium size yards. The durable 7-inch wheels can be adjusted to 3 different positions from 1.35-inches to 3.15-inches to meet the needs and conditions of your lawn. The fold down handle and compact design allows for easy storage.